Status of nutrient and sediment inputs from great Barrier Reef catchments and impacts on the Reef

Abstract

This publication does not have an abstract. The first paragraph of this chapter is displayed as the abstract.

Export of contaminants from the Great Barrier Reef Catchment The Great Barrier Reef World Heritage Area (GBRWHA), the world's largest marine protected area, is bordered by a catchment of 423,000 km2. Each year, an average of 380 km3 of rain falls on the Great Barrier Reef (GBR) catchment (1 km3 = 1 billion m3 or 1 million megalitres). Of this, an average of 70 km3 runs off into the GBRWHA carrying eroded soil, nutrients and other materials. These materials influence water quality and the ecology of nearshore ecosystems in the GBRWHA. Rainfall and runoff are highly seasonal, with ca. 2/3 occurring during the summer (December-April) wet season and varies greatly from year-to- year under the influence of summer monsoon, the occurrence of El Nino events and the unpredictable occurrence of cyclones. Much of the runoff to the GBRWHA occurs during short-lived flood events.